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Application of a new carboxylate-functionalized sugarcane bagasse for adsorptive removal of crystal violet from aqueous solution: Kinetic, equilibrium and thermodynamic studies

2014; Elsevier BV; Volume: 65; Linguagem: Inglês

10.1016/j.indcrop.2014.10.020

1872-633X

Bruno Christiano Silva Ferreira, Filipe Simões Teodoro, Aparecida Barbosa Mageste, Laurent Frédéric Gil, Rossimiriam Pereira de Freitas, Leandro Vinícius Alves Gurgel,

Minerals Flotation and Separation Techniques

A new carboxylate-functionalized sugarcane bagasse (SMA) was prepared via a solvent-free procedure involving esterification of sugarcane bagasse with Meldrum's acid. The optimized conditions provided SMA with a percent weight gain of 86.0% and 4.69 ± 0.20 mmol/g of carboxylic acid groups. SMA was characterized by FTIR, TGA, elemental analysis and SEM. Kinetic experiments showed that the amount of crystal violet adsorbed increased with increasing temperature and equilibrium was reached at 12 h. Adsorption kinetics followed a pseudo-second-order model. The Arrhenius and Eyring models were used to obtain the activation energy and changes in free energy, enthalpy, and entropy of activation for the adsorption process. The calculated activation energy (14.14 kJ/mol) suggested physical adsorption of CV onto SMA. The equilibrium data were well fitted to the Langmuir and Sips isotherms. Maximum adsorption capacity was 692.1 mg/g at 45 °C. Thermodynamic parameters such as changes in free energy, enthalpy and entropy were also determined.